Gas analyzer

Abstract

A gas analyzer comprising a Wheatstone bridge, consisting of resistance wires, which are provided in two mutually separated channels of a measuring block. The resistance wires of opposite legs of the bridge are contained in the same channel, wherein a reference gas may be conducted through a first one of said channels and a gas to be analyzed may be conducted through a second one of said channels. The current through the bridge is controlled during a measurement in such a manner that the resistance of the resistance wires in the second channel remains substantially constant.

I claim: 
     
       1. A gas analyser comprising a measuring block having two mutually separated channels, a first of said channels being adapted for conducting a reference gas therethrough and a second of said channels being adapted for conducting a gas to be analysed therethrough, a first Wheatstone bridge consisting of resistance wires provided in said two channels of the measuring block, the resistance wires of opposite legs of the first bridge being connected in the same channel, a second Wheatstone bridge, wherein the first Wheatstone bridge forms one leg of said second Wheatstone bridge, and means for controlling feeding current for said second Wheatstone bridge to maintain said second Wheatstone bridge balanced, wherein the leg of said second Wheatstone bridge connected in series with the first Wheatstone bridge consists of a resistance, the physical properties of which correspond to those of the resistance wires of said first Wheatstone bridge, the current per unity of cross-section for said resistance being smaller than for the total resistance of said first Wheatstone bridge. 
     
     
       2. A gas analyser according to claim 1, wherein said means for controlling include a differential amplifier having two inputs connected to the output terminals of the second Wheatstone bridge and controlling means for the feeding current of said second Wheatstone bridge, said controlling means being connected to the output of said differential amplifier. 
     
     
       3. A gas analyser according to claim 2, wherein one of the output terminals of the second Wheatstone bridge consists of a tapping point of a potentiometer connected in said second bridge.